Tired and Failing Mommy Basking in Grace

I struggle so much with knowing if I am following God's Will for my life and for my family right now. I am heavily involved in some great and important ministries such as children's ministry and MOPS. However, there is no greater ministry than the one of being mommy. With the weekly demands of children's ministry and the demands bi-weekly of MOPS, I am often not a happy mommy. I feel terrible and that I am a failure as a mom. My children deserve a mommy that is happy to be with them and is engaged in their play and activities. But instead, I am grumpy and impatient with their preschool antics. I want to intentionally parent my children. I want to intentionally discipline, teach and love them. How can I do that when I am thinking about the phone calls I need to make,the endless to-do lists just to make sure Sunday is good to go for all of the little ones? What am I suppose to be doing? This would be easy if I knew that these areas were not my gifts. I also think that my kids should understand that God expects us to serve others.But how do I find the balance? I feel so tired and so burdened with the responsibilities of mothering, leading two ministries, being a wife and a Christian. (It doesn't help that I serve the entire morning at church so I am never free to go to worship- I long, hunger for worship.) I also feel like a failure in so many other areas of life- finances, wife, maintaining a personal relationship with God.There are so many decisions I make that endanger or hurt my family. Many of my decisions also hurt my spiritual health as well. Despite how many times I try to start over and improve, I fail. I know I can't do this alone, however, I end up going my own way before too long.
This is not meant to be a pity party or beat myself up session, but simply an acknowledgement that I am a person who struggles daily- even minute by minute- to walk according to God's Will. I am very weak and without my Savior, I would be hopeless. I am so thankful that I bask in God's Grace. It is not because I am married to a wonderful, Godly man nor that I am ministry leader for two ministries or have college degrees or anything else I have done in my life. It is simply because God loves me. Loves me enough to sacrifice His Son for my sins and shortcomings. I am thankful that God's grace is more than enough for me, the sinner and screw-up. I am thankful that God's power can be made perfect as He helps me in all of my many weaknesses. (2 Corinthians 12:9)